The exemplary embodiment relates to processing links (references) in a markup language document. It finds particular application to XML documents, and will be described with particular reference thereto.
Extensible Markup Language (XML) is a widely used markup language which aids information systems in sharing structured data, encoding documents, and serializing data. Within XML and other markup language documents, there may exist many links (such as URL's) within the document that provide meaning and purpose to the document. Although the links inside the document are precisely defined through their syntactic and semantic structure, it is difficult and time-consuming to gather information about the context in which the links are used and where they are located inside a given document.
In a best case scenario, an XML document instance is compliant with an XML schema, e.g. XHTML, and thus it is possible to know where such a reference can be found, e.g., inside any img element, and more precisely, inside the value of its href attribute. The semantics of the reference is implicitly defined by the informal description of the HTML standard (it points to an image; it must be fetched through the URL and incorporated into the visual representation of the containing document).
However, many specific transformation operations can be envisioned which are focused on these referential objects. Currently, there are no methods or tools that simplify these operations and make them more reliable and easier to specify.
The present exemplary embodiment provides a system and a method for expressing link specific schemas, validations and transformations which can be complementary to general purpose schemas.